Method of supplying steam to the radiators of steam heating systems



' 11: W Jan 14, w F L RAYMOND 9 w METHOD OF SUPPLYING STEAM Tb THE RADIATQRS OF STEAM HEATING SYSTEMS Filed June 22, 1931 9 Sheets-Sheet 1 Jan. 14 mm F. n. RAYMOND mm w METHOD OF SUPPLYING STEAM TO THE RADIATORS OFSTEAM HEATING SYSTEMS METHOD OF SUPPLYING STEAM TO THE RADIATORS OF STEAM HEATING SYSTEMS Ffid lun 2, 1931 9 Sheets-Sheet 3.

an. M, 1936.. F. n. RAYMOND METHOD OF SUPFLYING STEAM TO THE RADIATORS O F STEAM HEATING SYSTEMS Filed June 22, 1931 9 Sheets-Sheet 4 9 F. ll. RAYMOND I METHOD OF SUPPLYING STEAM T O THE RADIATORS OF STEAM HEATING SYSTEMS Filed June 22, 1951 9 sheets-sheet 5 Jane M, WW. F. a. RAYMOND A fi fi METHOb OF SUPPLYING- STEAM TO THE RADIATORS OF STEAM HEATING SYSTEMS Filed June '22, 19 31 9 Sheets-Sheet fled 0 5 J, M 110 IF. u. RAYMOND METHOD OF SUPPLYING STEAM TO THE RADIATORS OF STEAM HEATING SYSTEMS Filed June 22, 1951 9 Sheets-Sheet 7 J 7 11 9 g9 J20 7 J16 H I? 2 ii JZZ Jan. M1 B. F L A N NEE METHOD OF SUPPLYING STEAM TO THE RADIATORS OF STEAM HEATING SYSTEMS Filed June 22, 1951 9 Sheets-Sheet 8 METHOD OF SUPPLYING STEAM TO THE RADIATORS OF STEAM HEATING SYSTEMSv 9 Sheets-Sheet 9 inwerz N w v a o mmN M 2 M w J d F m 1 F a Mn. Ml-

Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE j METHOD OF SUPPLYING STEAM TO THE RADIATORS OF STEAM HEATING TEMS SYS-

In the operation oi steam heating systems as commonly provided the steam entering the feeder pipes flows first into those radiators nearest the boiler thereby producing unequal heating of the radiators. While this condition is not serious when the system is operated under continuous pressure, it is serious when the system is operated intermittently, as for example when the boiler is fired by a start and stop oil burner, because the radiators nearest the boiler will be heated for a longer time than the others each time the burner operates, and. this causes a greater amount of heat to be delivered to the first rooms than to the last rooms.

One of my objects is to provide for the heating up of all of the radiators of a steam heating system substantially simultaneously, as distinguished from the heating of those radiators nearest the boiler before the others thereoi become heated, thereby avoiding the objections above noted.

Generally stated my invention consists in improvements in the venting of the air from steam heating systems to the end that the air in the radiators of the systems will remain trapped therein until all of the air has been removed from the steam mains.

Referring to the accompanying drawings:

7 Figure l is a view in elevation of a one-pipe steam heating system illustrating one of the ways of practicing my improved method.

Figure 2 is a similar View of a. modification of the system of Fig. 1 and illustrating another way of practicing my improved method.

Figure 3 is a similar view of another one-pipe steam heating system in which the steam is fed downward from an overhead steam main, and illustrating still another way of practicing my improved method.

Figure 4 is a similar view of a two-pipe steam heating system and illustrating still another way of practicing my improved method.

Figure 5 is a similar view of a modification of the system shown in Fig. 4 and illustrating still another way of practicing my improved method.

Figure 6 is a similar View of a large two-pipe steam heating system wherein the steam is fed to down-feed risers from an overhead steam main and illustrating still another way of practicing my improved method.

Figure 7 is a similar view of another two-pipe steam heating system and illustrating still another way of practicing my improved method.

Figure 8 is a vertical sectional view of a special valve forming a part of the system shown in Fig. 7.

Figure 9 is a view in elevation of a steam heating system of the Wet return type and illustrating still another way of practicing my improved method.

Figure 10 is a longitudinal sectional view of a check-vent valve forming a part oi. the installation of Fig. 9.

Figure 11 is a similar view of another vent valve forming a part or the installation of Fig. 9.

Figure 12 is a view in elevation of a steam heating system of the dry return type and illustrating still another Way of practicing my improved method; and

Figure 13, a view in sectional elevation of a float-equipped vent valve forming a part of the installation of Fig. 12.

Referring to the system shown in Fig. l, a boiler 9 supplies steam through a pipe in to a steam main II,. the steam being supplied from the steam main II to the radiators, represented at it, through riser pipes M, the water of condensation from the radiators l3 flowing by gravity back to the boiler 9 through the risers IS, the steam mains II and return lines l5 and I6 connected with the bottom of the boiler 9, the steam main sloping at its opposite ends toward. the return lines l5 and I6 as shown.

Each radiator I3 is equipped with a thermostatic vent valve represented at I! which may be of a type commonly used for the purpose of permitting air to escape from the radiator but preventing the esoape of steam therefrom, except that the vent valves I! in this case are each provided with a weight or spring (not shown) to hold the air-escape valve against its seat until a predetermined pressure is attained in the ra diator equipped therewith.

At the ends of the steam main ll similar vent valves represented at l8 are provided, these valves being designed to! open to the passage of air at a pressure considerably below that at which the vent valves I! open to the flow of air therethrough, the air escapement valves proper of the valves l8 preferably presenting a large area.

In operation this system functions as idllows: Assuming the steam main l l to be cold and full of air, generation of steam in the boiler 9 causes steam to flow therefrom through the steam main l l, resulting in an increase of the pressure in this main thereby forcing the air therein out through the vent valves l8, the vent valves l'l remaining closed inasmuch as the latter open at a higher pressure than the vent valves l8, thus venting the steam main before the radiators are vented. Since the valves 18 are of relatively large capacity, it will not be possible to build up an appreciable pressure in the system until they close. Therefore, the steam supplied to the main I I will flow out to the ends of the latter in preference to flowing into the radiators from which no air can escape at the lower pressure. When steam reaches the ends of the steam main II the vent Valves l8 automatically close by thermostatic action of the steam thereon; and as soon as both of the valves l 8 close, further generation of steam in the boiler will increase the pressure in the system to a point where the valves I1 open and permit of the discharge from the radiators I3 01' the air trapped therein, thus venting the radiators alter the steam main has been vented. The steam is thus simultaneously, and at substantially the same pressure, supplied to all or the radiators. By providing the valves ll of small size, it will not be possible for one of these valves to vent air in sufficient volume to prevent further raising of the pressure in the system.

Thus there will be a material increase in pressure in the system when the valves [8 close and this material increase in pressure will cause all oi the valves IT to open, even though there may be a slight difference in their opening pressures and effect simultaneous supply of steam to all of the radiators.

Referring to the system shown in Fig. 2, a boiler represented at i9 supplies steam through a pipe to a steam main 2i, this main supplying steam, through risers 23, to radiators represented at 24 equipped with thermostatic vent valves 25 of standard design.

Condensation from the radiators 24 is returned, by gravity, to the boiler l9 through the risers 23, the steam main 2| and return air lines 26 and 21, the latter opening into the bottom of the boiler I 9.

This arrangement also comprises a vacuum pump 28 shown as driven by an electric motor 29, the inlet of this pump being connected with a pipe 30 which opens into pipes 31 and 32 in communication with the ends of the steam main 2| and the outlet thereof provided with an outwardly opening check valve 34, the pipes 3| and 32 having interposed therein thermostatic traps 33, as for example of standard design.

In operation, the entire system will be held under partial vacuum by the vacuum pump 23 so long as the thermostatic traps 33 are open. Therefore when the boiler I9 starts to generate steam, the steam will flow out to the ends of the steam main 2| rather than into the branch risers 23 and radiators 24, thus venting the steam main before the radiators are vented. As soon as the steam reaches the thermostatic traps 33 the latter automatically close so that further generation of steam in the boiler l9 produces a rise in pressure in the system above atmospheric pressure thereby causing steam to enter all of the risers 23 simultaneously as described in connection with the operation of the system shown in Fig. 1, thus venting the radiators after the steam main has been vented, it being understood that the rise above referred to of the pressure in the system forces open the vent valves 25 to permit the air to vent from the radiators.

Referring to the system shown in Fig. 3, a boiler represented at 35 connects, by an upwardly extending pipe 36, with an overhead main 3'! from which steam is supplied to down-feed risers 38 constituting parts of the main 3! and opening into the pipe 37 at different pointsalong the latter as shown. Each riser 38 is shown as connected by pipes 39 with a vertical series of radiators 40 each of which is provided with a thermostatic vent valve 4| of standard design. The system shown is provided for the supplying of steam to radiators a plurality of which are located on each floor of a building, as for example, and as shown in the drawings, tour floors.

The condensation from the radiators 40 flows, by gravity, from the radiators to the risers 38 and thence to float traps 42 of standard design which operate to permit the passage of water to a return line 43 connected with these traps by pipes 44, but which close to the passage of air or steam therethrough.

The system also comprises a vacuum pump represented at 45 the inlet of which communicates with a pipe 46 which extends upwardly into a receiver 41 in communication at its top with the pipe 43, by a pipe 48, the outlet of the pump 45 represented at 49 being provided with an outwardly opening check valve 50 like the valve 34 of Fig. 2. The bottom of the tank 41 communicates by a pipe 5| with a boiler-reed pump 52 the outlet of which communicates by a pipe 53 with the bottom of the boiler 35.

The system also comprises thermostatic traps represented at 38 communicating with the lower portions of the down-feed risers 38 by pipes 38 and with the return line 43 by pipes 43 the traps 38 permitting of the passage of air from the risers 38 to the return line 43 and the escape therefrom through the check valve 53, by the operation of the pump 45, but closing to the passage of steam.

The operation of this system is similar to that of the system shown in Fig. 2, the only diiierence being in the addition of the float traps 42 which permit the return line 43 to be used as the air line as well as the condensate return line.

So long as any of the thermostatic traps 38' are cold indicating that steam has not yet filled the steam main 3'! and risers 38, the system will be maintained under a partial vacuum by the vacuum pump 45 and the air in the radiators 4i] will remain trapped therein. When all the steam traps 38 become closed by the presence 01' steam therein, the vacuum pump 45 no longer exerts suction on the risers 38, the float traps 42 being closed as they open only upon the collection of condensate therein, and thus in the continued opera tion or the boiler the pressure in the pipes 36, 31 and 38 rises above atmospheric thus forcing the air out of the radiators 40 through the vents and simultaneously supplying steam to all or the radiators.

Referring to the system shown in Fig. 4, which constitutes an embodiment of my invention in a so-called two-pipe steam heating system of common design, the boiler 54 connects by a pipe 55 with a steam main 56 from which steam is supplied through risers 51 to radiators represented at 58. The radiators 58 are provided with therm0- static steam traps 59 which open into a return line 60 discharging through a pipe GI having a short water leg section 62, into the bottom oi a separator 63 equipped with an outwardly opening check valve represented at 64. The separator 53 is connected by a pipe 65 with an alternator 66 as for example of standard design and to which the condensate in the separator 6 3 flows through the pipe 65. The upper end of the alternator 56 connects by a pipe 61 with the steam main 56 and the condensate-outlet of the alternator 66 connects by a pipe 68 with the bottom oi the boiler 55. This alternator is provided in accordance with common practice for the purpose of returning condensate to the boiler against pressure.

The upper portion of the separator 63 connects, by pipes 69, with thermostatic traps I0 located at the ends of the steam main 56, the traps I0 being open to the flow of air and water therethrough and closing to the passage of steam.

The operation of this system is as follows: The generation of steam in the boiler 54 causes steam to flow through the pipe 55 and into the steam main 56. As the steam progresses into the main 55 it displaces the air therein, the air following the path of least resistance to the atmosphere which is through the steam traps Ill, return line 59, separator 53, and check valve 64 to the atmosphere, rather than through the risers 51, radiators 58, traps 59, return line 60, pipe 6 I, with. its water leg 62, separator 63, and check valve 55, thus venting the steam main before the radiators are vented. Even without the water leg 52 there would be a greater flow of air from the return line 55 than from the return line 60, but the water leg 52 in the return line 69 produces a definite and positive seal which prevents the flow of any air therethrough until the pressure in the return line 60 rises sufiiciently above atmospheric pressure to blow the water out of the water leg 52.

Steam will therefore flow along the steam main 55 without branching off into the risers 59, until the steam main 56 is completely filled with steam which causes the thermostatic traps 'Iil to close. The closing of the thermostatic traps I0, due to the presence of steam therein, prevents the further escape of steam therethrough and the continued generation of steam in the boiler 54 creates an increase in pressure in the system, this pressure finally becoming sufficient to blow the water from the water leg 52 and permit the escape of air from the radiators 58 through the return line 55, thus venting the radiators after the steam main has been vented. Inasmuch as the steam main 55 is filled with steam, the steam, in the venting of the radiators as stated, will start to how into all the radiators substantially simultaneously.

In this arrangement it is desirable, though not necessary, that the piping between the steam traps 59 and the separator be equipped with an inwardly opening check valve as indicated at 5 I which permits breaking of the vacuum in the return line 55 thereby preventing leakage of air into the steam main which, as will be manifest, it is desired be avoided.

Referring to the system shown in Fig. 5, which is of the so-called two-pipe steam heating type of system equipped with a combination vacuum and condensation return pump, the boiler, represented at H, supplies steam through a pipe I2 to a steam main I3 connected, by pipes I4, with radiators I5 provided with steam traps I6 opening into a return line 11 communicating with a pipe Iii having a lower, water leg, section I9 opening into the bottom of a receiver 80.

Steam traps 8| are provided at the ends of the main I3 these traps being connected with a return line 82 connected with a pipe 83 which opens into the top of the receiver '80.

The receiver 85 forms an element of a combination vacuum and condensation pump structure represented generally at 84 and comprising a vacuum pump 85 the inlet oi which communicates with a pipe 86 extending upwardly into the receiver and the outlet of which connects with a pipe 8! having an outwardly opening check valve 88. The structure 84 also comprises a boiler feed pump 89 connected at its inlet, through a pipe 95, with the bottom of the receiver and, by a pipe 9 I, with the bottom of the boiler I I.

The operation of this system is as follows: In starting this system the vacuum pump 85 will withdraw air from the mains I3 through the steam traps 5|, return line 82, pipe 83, receiver 80, pipe 8 exhausting the air through the check valve 88, the air in the radiators '15 remaining therein due to the greater resistance to flow through the risers I4, radiators I5, return line 'I'I, pipe I8, and its water leg I9, the steam main thus being vented before the radiators are vented. Steam will therefore be drawn out to the ends of the steam main I3 before the steam branches off into the risers I4. Upon the closing of the steam traps BI by the presence of steam therein, and thus throughout the extent of the steam main it, the suction created by the vacuum pump 85 can no longer be relieved by flow through the traps 8i,

pipes 82 and 83 and separator 50, whereupon the vacuum created by the pump increases in the receiver 80 until it is sufficient to overcome the resistance of the water in the water leg l9 whereupon the water will be blown from this leg and air will then be drawn from all of the radiators I5 substantially simultaneously through the steam traps I6, return lines Ii', pipe '38, separator 85, pipe 85, pump 85, and check valve 83 to the at mosphere, thus venting the radiators after the steam main has been vented and as at this time the steam mains I3 are filled with steam, the entry of steam into all of the radiators '55 will occur substantially simultaneously.

Referring to the system shown in Fig. 6 which is of the so-called two-pipe steam heating type of system widely used in tall buildings, and comprising down feed risers, the elements of this system are substantially the same as those shown in Fig. 5 with the exception that the down feed risers constitute portions of the steam main. In this system the boiler is represented at 92 and connects with a pipe 93 opening into an overhead steam main 54 from which down feed risers 95 lead. Each riser shown as connected by pipes 55 with a vertical series of radiators 97 each of which is provided with a steam trap 33 which opens into a return line 89 connected with pipes I85 opening into a pipe till having a lower water leg I52 opening into the bottom of a receiver E53.

At the lower ends of the risers 85 are relatively large thermostatic traps Hi4 connected with a return. line I535 opening into a pipe HIS which communicates with the top of the receiver I03. A combination vacuum and condensation pump is represented at IUI, the vacuum pump I53 of which connects at its inlet with a. pipe I69 opening into the upper end of the receiver I53 and its outlet connecting with a pipe H5 having an upwardly opening check valve III. The boiler feed pump element of this apparatus is represented at H2, this pump connecting at its inlet with a pipe I I3 which opens into the bottom of the receiver ")3 and at its outlet with a pipe I it which opens into the bottom of the boiler 92.

As the system now being described functions in the same manner as the system shown in Fig. 5 repetition of the description of the operation is unnecessary.

It will be understood from the foregoing that in the systems 'shown in Figs. 1 to 6, inclusive, the filling of the steam mains, before flow of steam into the radiators, is accomplished by providing greater resistance to the flow of air through the radiators than from the steam mains thereby insuring the filling of the steam mains before starting to fill the radiators with steam. In other words, air flows from the steam mains at a lower pressure than it does from the radiators.

The method may also be practiced by a system wherein the air is vented from the radiators at the same pressure as that it which it is vented. from the steam mains, Fig. 7 showing such a system and employing as an element thereof a special valve, shown in detail in Fig. 8, which operates to cause the air to be forced from the steam main before starting the flow of the air from the radiators.

The system shown in Fig. 7 comprises a boiler IIS connected with a pipe II6 opening into a steam main II'I connected, by risers I I8, with radiators I I9 equipped with steam traps I which communicate through branch pipes I2I with a dry return line I22, provided with an inwardly opening check valve I 22" for the purpose above explained in connection with check valve fil of Fig. 4. The steam main Ill and the dry return line I22 connect with pipes I23 and I24, respectively, which open at their lower ends into a wet return line I25 for draining by gravity into the latter condensation in the lines I I1 and I 22. The wet return line I25 drains into an alternator I26 of common design which returns the condensate to the boiler through pipe I21 even though the pressure in the boiler may be greater than the pressure in the return line.

The system now being described also comprises a special form of valve represented generally at I28 the details of which are shown in Fig. 8. This valve comprises a casing I29 divided by partitions I30 and I3I into an upper compartment I32, a lowercompartment I33, and an intermediate compartment I34. The compartment. I32 communicates with the steam line I I! beyond the connection of the latter with the drain pipe 29 and the compartment I33 communicates with the dry return line I22 beyond its connection with the drain pipe I24; and the compartment I34 connects by a pipe I35 with an outwardly opening check valve I36.

The partitions I30 and I3I contain ports I37 and I38 extending therethrough and with which oppositely facing conical valves I39 and I40 cooperate. The valves I39 and I40 are provided on the stem I4I of a thermostatic bellows I42 mounted on the top of the casing I29 this bellows being shown as of the common expansible corrugated chamber type containing liquid that boils at a temperature slightly under that of steam. The valve member I40 is shown as adjustable along the stem I4I relative to the valve I39, these valves being so spaced that at no time are both valves seated.

The operation of this system is as follows: Assuming the system to be cold, the starting up of the boiler H5 causes steam to flow through pipe I I6 into the steam main I H. In the cold condition of the apparatus the valve I40 will be seated to close the port I38 and the valve I39 unseated to open the port I31 whereby the steam main II! will be in communication through the compartments I32 and I34 with the check valve I36. Thus the air in. the steam line ill will be driven therefrom, the radiators H9 being closed to the escape of air therefrom by the closed condition of the valve I40, thus venting the steam main before the radiators are vented. When the steam main I I! becomes filled with steam and the steam contacts with the thermostatic bellows I42, this bellows expands forcing the valve I39 to seated position and closing the port I31 and forcing the valve I 40 to open position thereby closing the steam line to the escape of steam therethrough to valve device I28 and opening the dry return line I 22 and consequently the radiators for the escape therefrom of the air therein out through the check valve I36, thus venting the radiators after the steam main has been vented. Inasmuch as the steam line II! has been filled with steam before the air may vent from any of the radiators, the actuation of the valve I28 to close the steam main II! to the escape of steam therefrom and open the return line I22 to the atmosphere, permits the air in the radiators to escape substantially simultaneously from all of the radiators and consequently the steam will flow into all of the radiators substantially simultaneously.

Referring to the system shown in Figs. 9, 10 and 11, the boiler represented at I43 connects by a pipe I44 with a steam main I45 from which the steam is supplied, through risers I46, to radiators represented at M1. The radiators I41 are provided with thermostatic steam traps I48 which open into a dry return line pipe I49 connected with a pipe I50, the latter opening into a pipe I5I leading into a return trap I52 the outlet of which connects by a pipe I53 with the bottom of the boiler I43, the trap I52 also being connected with the steam line I44 by a pipe I54.

At the ends of the steam main I45 are vent valves I55 comprising-chambers I56 communicating through their side Walls with the ends of the steam main I45 and through their bottom walls with the upper ends of pipes I5'I which open into the return line pipe I50, the water and air or steam discharging from the steam line I45 into the chambers I56. The chambers I 56 are in effect separating chambers in which the water settles to the bottoms thereof and flows out through the pipes I5'I to the wet return line pipe I50, air or steam entering the chambers I56 rising to the top of these chambers.

The chambers I56 contain outlet ports I58 shown as opening into supplemental chambers I59 having vents I60 the ports I58 being normally closed by disks I6I located in the supplemental chambers and upwardly displaceable.

The chambers I56 also contain thermostatic valve mechanisms controlling the outputs I58 and comprising expansive elements I62, shown as bellows, supported on spiders I63 in the chambers I56 and having valves I64 which are normally open but which close when the elements I62 become heated by contact therewith of steam.

The return line I49 is connected with a vent valve I65 (Fig. 10) comprising a casing I66 open to the line I49 and containing an outlet port I61 in its top wall which opens into a chamber I68 having side vents I69 and housing a disk II0 which is much heavier than the disks I6I and normally closes the outlet port I61, but which is vertically displaceable to uncover this port, the line I49 also having an inwardly opening check valve I'II functioning for the purpose above explained as to valve 6 I.

The operation of the system is as follows:

The generation of steam in the boiler I43 causes steam to flow through the pipe I44 and into the steam main I45. As the steam progresses into the main I45 it displaces the air therein which flows into the vent valves I55 lifts the valve disks I6I and discharges to the atmosphere, thus venting the steam main before the radiators are vented. While the vent valve I65, which is open to the outlets of the radiators, is also open to the steam main I45, this valve remains closed during the venting of the air from the steam-main because the disk I19 is heavier than the disks IGI. Upon the passage of steam into both valves I55 and the heating of the expansion elements I52 therein the valves I64 close the vents I 60 and upon rise of pressure of steam in the system valve I55 automatically opens to vent the radiators I41. Thus the steam line will become completely filled with steam before any steam can enter any of the radiators and when the steam line thus becomes filled with steam, steam will start to enter all of the risers M6 simultaneously thus heating all of the radiators simultaneously.

It will be understood that it is not necessary that both of the valves I55 vent at the same pressure so long as they both vent at a pressure substantially below that at which the vent I55 opens. Should valves I55 vent at diiferent pressures the one venting at lower pressure will close, and the steam will fill this end of the steam line first and therefore fill theother end before the valve I65 opens to permit steam to flow into the radiators.

Referring to the system shown in Figs. 12 and 13,'the boiler I12 connects by a pipe I13 with a steam main I'I I- communicating with risers I15 opening into the radiators I16 the outlets of which open into pipes I11 communicating with a return line I18. A return trap I19 connects at its upper end with pipes If and I86 which open, respectively, into the steam main HI and the return line I18, and opens at its bottom into a pipe discharging into the bottom of the boiler I12. I

At the ends of the steam main I1 and the return line I18 are float-equipped thermostatic vent valves I82 comprising casings I83 containing main and supplemental chambers I84 and IE5, respectively, communicating through ports I36 in the top walls of chambers I35, the pipe I15 opening into the main chambers I84 and the pipe I18 opening into the supplemental chambers I85. The water of condensation fiowing inthe pipe I'I I returns to the boiler I12 through the casings I83 and to control this flow the valve structures I82 are provided with valves I81 operated by floats I88 in the chambers I84 and maintaining the chambers I 85 closed to chambers I84 except when the water of condensation accumulates in the chambers I84 to such a height as to force the fioats I83 to valve-raising position.

The valves I82 also comprise thermostatic means for venting the line I14 of air shown as of the same construction as the valves I55 of the preceding figures, the outlet-port-controlling disks of which are represented at IE9 and the expansion-element-controlled valves at I90.

The line I18 is also provided with a vent valve IQI of the same construction as the vent valve W5 and operative to open position by the exertion against its outlet-port-controlling disk of greater pressure than required to open the disks I89 of valves I32 as in the case of valve I65.

The operation of the system now being described is the same as that shown in Fig. 9 except that the water in the wet return line of Fig. 9 operates to prevent the flow of air from the steam main into the return line, whereas in the system of Fig. 12 the float valves act to prevent the flow of air from the steam main into the return line.

The line I18 is also shown as provided with an inwardly opening check valve I92 which performs the same function as that performed by the check valve 6 I of Fig. 4.

It will be noted that as to those of the systems above described which involve the venting of the steam mains at a lower pressure than that at which the radiators are vented, one of the features is the provision of a single air-vent valve for all of the radiators whereby simultaneous filling thereof with steam is assured, whereas a plurality of vents may be provided for the steam main and these vents function at different pressures provided they open at lower pressures than the vent for the radiators.

While I have illustrated and described certain constructions of apparatus by which my improved method may be practiced, I do not wish to be understood as intending to limit it thereto as the method may be practiced by the use of other constructions of apparatuses without departing from the spirit of my invention.

What I claim as new, and desire to secure by Letters Patent, is:

l. The method of supplying steam substantially simultaneously to a plurality of radiators connected with a steam main, which consists in first venting the air from the steam main while maintaining the air in the radiators against escape therefrom, and thereafter venting air from the radiators.

2. The method of supplying steam substantially simultaneously to a plurality of radiators connected with a steam main, which consists in foreing the air from the steam main by the pressure of steam supplied thereto while maintaining the air in the radiators against escape therefrom, and thereafter forcing the air from the radiators by the pressure of the steam.

3. The method of supplying steam substantially simultaneously to a plurality of radiators connected with a steam main, which consists in venting the air from the steam main and separately therefrom venting the air from the radiators and in maintaining the air in the radiators against escape therefrom until the steam main has become filled with steam.

' 4. The method of supplying steam substantially simultaneously to a plurality of radiators connected with a steam main, which consists in venting the air from the steam main and separately therefrom venting the air from the radiators and in maintaining the air in the radiators against escape therefrom until the steam main has become filled with steam at a predetermined pressure.

5. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and at the other end to a system of air collecting piping which consists in first venting the air from the steam main while maintaining the air in the system of air collecting piping against escape therefrom and thereafter venting the air from the system of air collecting piping.

6. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and at the other end to a system of air collecting piping which consists in first venting the air from the steam main while maintaining the air in the system of air collecting piping against escape therefrom and thereafter venting the air from the system of air collecting piping at a single point.

7. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and at the other end to a system of air collecting piping which consists in forcing the air from the steam main to the atmosphere by the pressure of steam supplied thereto while maintaining the air in the system of air collecting piping against escape therefrom and thereafter forcing the air from the system of air collecting piping to the atmosphere by the pressure of the steam.

8. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and at the other end to a system of air collecting piping which consists in forcing the air from the steam main to the atmosphere by the pressure of steam supplied thereto while maintaining the air in the system of air collecting piping against escape therefrom and thereafter forcing the air from the system of air collecting piping at a single point to the atmosphere by the pressure of the steam.

9. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and'at the other end to a system of air collecting piping which consists in venting the air from the steam main and separately therefrom venting the air from the system of air collecting piping, and in maintaining the air in the system of air collecting piping against escape therefrom until the steam main has become filled with steam.

10. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and at the other end to a system of air collecting piping which consists in venting the air from the steam main and separately therefrom venting the air from the system of air collecting piping at a single point and in maintaining the air in the system of air collecting piping against escape therefrom until the steam main has become filled with steam.

11. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and at the other end to a system of air collecting piping which consists in venting the air from the steam main and separately therefrom venting the air from the system of air collecting piping, and in maintaining the air in the system of air collecting piping against escape therefrom until the steam main has become filled with steam at a predetermined pressure.

12. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and at the other end to a system of air collecting piping which consists in venting the air from the steam main and separately therefrom venting the air from the system of air collecting piping at a single point and in maintaining the air in the system of air collecting piping against escape therefrom until the steam main has become filled with steam at a predetermined pressure.

13. The method of supplying steam substantially simultaneously to a plurality of radiators connected to a steam main which comprises venting the air from the steam main, separately therefrom venting the air from the radiators and arresting the venting of air from the radiators until the pressure in the radiators exceeds the pressure at which air vents freely from the steam main.

14. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and at the other end to a system of air collecting piping which comprises venting the air from the steam main, separately therefrom venting air from the system of air collecting piping, and arresting the venting of air from the system of air collecting piping until the pressure in the system of air collecting piping exceeds the pressure at which air vents freely from the steam main.

15. The method of supplying steam substantially simultaneously to a plurality of radiators connected with a steam main which comprises venting the air from the steam main to the atmosphere, venting the air from the radiators to the atmosphere, and arresting the venting of air from the radiators until the pressure in the radiators exceeds the pressure at which air vents freely from the steam main.

16. The method of supplying steam substantially simultaneously to a plurality of radiators connected with a steam main which comprises venting the air from the steam main into a subatmospheric space and subsequently venting the air from the radiators to the atmosphere.

17. The method of supplying steam substantially simultaneously to a plurality of radiators connected with a steam main which comprises venting the air from the steam main into a subatmospheric space, venting the air from the radiators into a sub-atmospheric space, and maintaining the space into which air vents from the steam main at a lower absolute pressure than the space into which the air vents from the radiators.

18. The method of supplying steam substantially simultaneously to a plurality of radiators connected with a steam main which comprises venting the air from the steam main, separately therefrom venting the air from the radiators, and in thermostatically sealing the air in the radiators until the end of the steam main has become heated by the presence of steam therein.

19. The method of supplying steam substantially simultaneously to a plurality of radiators connected at one end to a steam main and at the other end to a system of air collecting piping which comprises venting the air from the steam main, separately therefrom venting air from the system of air collecting piping, and thermostatically sealing the air in the system of air collecting piping until the end of the steam main has become heated by the presence of steam therein.

20. The method of supplying steam substantially simultaneously to a plurality of radiators connected to a steam main which comprises, independently venting air from the steam main and from the radiators in the order of venting the air from the steam main before starting the venting of the air from the radiators.

FRED I. RAYMOND. 

